Find the value of λ for which the planes x – 4y + λz + 3 = 0 and 2x + 2y + 3z = 5 are perpendicular to each other.
To find an angle in Cartesian form, for the standard equation of planes
For θ=90°, cos90°=0
On comparing with the standard equation of the plane,
2 + (-8) + 3λ=0
-6 + 3λ=0
λ=2
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